GB845470A - Improvements in or relating to ribbon-feeding mechanism - Google Patents

Abstract

845,470. Ink-ribbon mechanisms. INTERNATIONAL COMPUTERS AND TABULATORS Ltd. Feb. 17, 1959 [March 7, 1958], No. 7463/58. Class 100(4) An ink-ribbon feeding mechanism which feeds a ribbon 1 to and from spools 2, 2A, comprises a drive shaft 6 adapted to be clutched alternatively to drive one or other of the spindles 3, 3A. The clutches are controlled by a common change-over arm 16 pivoted at 17 and adapted to engage one of the clutch members 12, 12A secured to the spindles 3, 3A with one of the dog members 10, 10a driven by gearing from the shaft 6. The change-over arm 16 is actuated by trigger devices associated with each spool whenever the amount of tape on a spool is reduced to a predetermined level. Each trigger device, Fig. 2, comprises a release lever 21A which is held against the action of a spring 27A by a release arm 35A until an arm 30A, having a roller 33A held in contact with the ribbon 1 by a spring 34A, through a firing pin 38A, disengages a tooth 39A to allow the spring 27A to move the release lever 21A to engage a bell crank arm 22A or the arm 22 of the spool 2 which by a link 18 or 18A, rocks the arm 16 first to disengage one clutch and then to engage the other so that the spindles 3, 3A are never both positively driven. After a change over of drive as ribbon is wound on to the driven spool the arm 30A is forced outwards withdrawing the release arm 21A until the tooth 39A can again engage a notch 40A to hold it with the spring 27A tensioned. Each spindle 3, 3A has a brake device to prevent ribbon sag comprising a collar 42 secured to the spindle and a friction pad 41 and a spring urged second collar 43 adapted to be engaged by the hooked end of a spring 47 to retard rotation of the spindle when it is un-clutched from the drive shaft 6.